Portable system for the production of oxygen

ABSTRACT

A portable oxygen generating system is provided that comprises a reaction chamber, a feed system for providing and controlling hydrogen peroxide solution to the reaction chamber, and a cooling/condensing system for cooling the hot oxygen and water vapor leaving the reactor and condensing and removing water. The portable chemical oxygen generation system produces humidified, breathable oxygen, that is substantially free of hydrogen peroxide and other contaminants, at a controlled flow and temperature over an extended period of time.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Patent ApplicationNo.: PCT/IB2020/053228 filed Apr. 3, 2020, which claims priority to U.S.Provisional Patent Application No. 62/828,475, filed on Apr. 3, 2019,the contents of each is incorporated herein by reference.

FIELD OF THE INVENTION

This disclosure is in the field of oxygen production, methods ofproducing oxygen, and chemical oxygen generators. More specifically,this disclosure provides a portable chemical oxygen generator providinghigh-purity breathable oxygen. The disclosure also provides anapparatus/system for the low-energy condensing of (water) vapor, forexample in removing the water by-product of oxygen generation.

BACKGROUND

Oxygen is a critical component of medical treatment. This treatment canbe chronic or acute. Supplemental oxygen can be lifesaving in emergencysituations, although the burden of providing oxygen during transport andin remote areas is substantial in cost, transport, and materials.

Oxygen cylinders are heavy and present a number of potential hazardsincluding combustion, detonation and projectile risks. Liquid oxygensystems provide a large amount of gas with a smaller footprint, but areheavy, exhaust gas over time, and present a burn risk if handledimproperly. In addition, the output of both of these oxygen systems isfinite and requires refilling, which presents logistical issues in farforward military operations. Simpler, lighter, and longer lasting oxygendelivery systems are needed for many emergency situations, includingmilitary and mass casualty operations.

Portable oxygen concentrators (POCs) and chemical oxygen generators(COGs) have been proposed as a solution. POCs, sometimes referred to asoxygen concentrators draw in air from the environment, which usuallycontains about 21% oxygen, and extract the nitrogen to supply oxygen ata concentration of up to 90-95%. Portable units generally produce up to6 l/min and larger devices (not portable) producing up to 25 l/min. Allthese devices are electrically operated and require a source ofcontinuous power, so a power failure will result in a failure of oxygensupply unless a standby generator, or a battery backup and powerinverter are available. Also, the low flow and lower pressure of gassupplied from the portable units limits their use for many emergencysituations.

Chemical oxygen generation was first suggested by the work of JosephPriestly when he discovered oxygen during his work with mercuric oxide.Priestly published his findings in 1775. In 1902, the “Lancet” reportedon Kamm's oxygen generator invention for medical use. The device usedchlorate as the oxygen source and when heated by a spirit lamp producedapproximately 4 cubic ft of oxygen before needing to be replenished withingredients. Chlorate candles have been used as a source of emergencyoxygen, for example in submarines. However, the oxygen-producingreaction of chlorate candles is very hot (about 700-800° C.), andaccordingly can be very hazardous.

POCs and COGs have been proposed for use in far forward militaryoperations and in disaster and mass casualty scenarios as alternativesto liquid and pressurized gaseous oxygen systems because of thelogistical challenges, weight, and explosive risks associated withliquid and pressurized gaseous oxygen systems. Evaluation of thecurrently available technologies shows that COGs can operate for only 30minutes or less, depending on the manufacturer and design, and theinability to adjust output makes the devices unsuitable for continuousclinical care or long-term operation. COGs may also have an oxygen flowrate that is too low for many emergency uses.

More recently, there has been interest in employing this technology inareas where providing oxygen in cylinders or in liquid form islogistically difficult or economically prohibitive such as during combatcasualty care, disaster situations, and in extreme rural environments inundeveloped countries. Simpler, lighter, and longer lasting oxygendelivery systems are needed for military and mass casualty operations.

The FDA dictates that a COG must provide a minimum of 6 L/min of oxygenflow for a minimum of 15 min (21 CFR part 868.5440). However, the USArmy demands a higher output, where the system must provide 8 L/min forat least 20 min. This is an increase of 75% in the total O₂ output, alevel not attainable by the available COGs. There exists a long feltneed for a portable, on-demand oxygen generator.

SUMMARY OF THE INVENTION

The present disclosure provides a chemical oxygen generation systemwhich produces humidified, breathable oxygen, that is substantially freeof hydrogen peroxide and other contaminants, at a controlled flow andtemperature over an extended period of time. In an aspect, the chemicaloxygen generation system can generate a constant flow of oxygen of morethan about 8 L/min and up to about 15 L/min, at a temperature of lessthan about 40° C. for more than about 30 minutes.

In one aspect, the portable oxygen generating system comprises areaction chamber, a feed system for providing and controlling hydrogenperoxide solution to the reaction chamber, and a cooling/condensingsystem for cooling the hot oxygen and water vapor leaving the reactorand condensing and removing water. The reaction chamber comprises acatalyst that facilitates the chemical decomposition of hydrogenperoxide to oxygen and water, an inlet for the introduction of hydrogenperoxide solution into the reaction chamber, and an outlet for therelease of oxygen and water vapor from the reaction chamber. Thehydrogen peroxide feed system comprises a hydrogen peroxide reservoirthat contains aqueous hydrogen peroxide solution and a feed flowregulator for controlling the rate of addition of the aqueous hydrogenperoxide solution into the reaction chamber. The cooling systemcomprises an inlet for receiving oxygen and water vapor, a condensercomprising two or more drains, each configured to drain water condensedfrom the water vapor in the cooling system, and an outlet for therelease of cooled oxygen gas with reduced water vapor.

It is an aspect of this disclosure to provide a portable device foroxygen generation comprising:

-   -   a. at least one reservoir for holding a hydrogen peroxide        solution;    -   b. one or more reaction chambers containing a catalyst, for        reacting hydrogen solution and producing oxygen and water vapor;    -   c. a feeding system for supplying hydrogen peroxide to the        reactor(s) from the reservoir;    -   d. a system for cooling in fluid communication with the outlet        of the reactor, that condenses and removes condensed liquid        water;    -   e. optionally, a drier situated between the reactor and the        cooling system for removing a portion of the water from the        oxygen stream;    -   f. optionally, drive system for moving liquid water to a storage        tank;    -   g. optionally, a hydrophobic membrane, for removing water at the        oxygen outlet of the cooling system; and    -   h. optionally, an oxygen flow regulator, for regulating oxygen        flow at the hydrophobic membrane outlet.

The cooling system may be an open system operatively located between thereactor outlet and the hydrophobic membrane (filter). The cooling systemis configured to cool oxygen gas flowing between the reactor and thefilter.

It is another aspect to provide a device as presented in any of theabove, wherein the reservoir is configured to hold hydrogen peroxide, ahydrogen peroxide complex or a hydrogen peroxide solution.

It is another aspect to provide a device as presented in any of theabove, wherein the hydrogen peroxide solution is at least 15% hydrogenperoxide, or is at least 20% hydrogen peroxide. The reservoir may be acartridge that detachably connects to the feeding system. The cartridgemay be configured to be instantly replaceable once the hydrogen peroxidesolution is depleted.

It is another aspect to provide a device as presented above, wherein thecartridge attachment system allows rapid attachment to the feedingsystem. The cartridge may be collapsible, have a collapsible liner, ormay be hard-sided or soft-sided.

It is another aspect to provide a device as presented above, wherein thefeeding unit is configured to generate pressure on a soft-sidedcartridge. The pressure may be generated by a spring, a piston orpneumatic pressure. Additionally or alternatively, the feeding systemmay comprise a pump, for example a pump selected from a displacementpump, peristaltic pump, syringe pump, piston pump, plunger pump, screwpump and reciprocating pump.

It is another aspect to provide a device as presented in any of theabove, wherein the reactor is configured to decompose hydrogen peroxideto water and oxygen. The reactor contains a catalyst that facilitatesthe chemical decomposition of hydrogen peroxide to oxygen and water. Thecatalyst may comprise one or more active compounds selected from ametal, a metalloid, an alloy of a metal, an alloy of a metalloid, acompound of a metal and a compound of a metalloid. The catalyst mayadditionally comprises an electronegative element.

It is another aspect to provide a device as presented in any of theabove, wherein the device additionally, and optionally, comprises acatalytic filter. The catalytic filter, if present, may comprise atleast one catalyst, the catalyst comprises one or more active compoundsselected from a group consisting of a metal, a metalloid, an alloy of ametal, an alloy of a metalloid, a compound of a metal and a compound ofa metalloid. The catalytic filter may comprise the same catalyst(s) asthe reactor, or may comprise a different catalyst.

It is another aspect to provide a device as presented in any of theabove, wherein the cooling system comprises a heat sink. The coolingsystem may additionally comprise at least one fan for facilitating theremoval of heat from the cooling system. The fan may be an electric fan.

It is another aspect to provide a device as presented in any of theabove, wherein the cooling system comprises a condenser. The coolingsystem comprising a condenser is configured to facilitate the drainingof liquid water condensed by the cooling system. The draining system maybe configured to drain the condensed water from at least one point alongcooling system.

It is another aspect to provide a device as presented in any of theabove, wherein the condensed water is drained immediately andcontinuously. The cooling system may additionally comprise a receptaclefor collecting the condensed water.

It is another aspect to provide a device as presented in any of theabove, wherein the hydrophobic membrane is constructed from a materialselected from one or more of a group consisting of acrylic copolymers,polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF),polysulfones and polycarbonates.

It is another aspect to provide a device as presented in any of theabove, wherein the oxygen flow regulator is a heat/mass oxygen (O₂) flowmeter configured for real-time flow measurement.

It is another aspect to provide a device as presented in any of theabove, wherein the device additionally comprises an electronic controland display unit, comprising one or more of:

-   -   a. Unit sensors;    -   b. Unit controls;    -   c. Unit alerts; and    -   d. Unit feedback circuits.

The control unit may be based on a designated Printed Circuit Board.

It is another aspect to provide a device as presented in any of theabove, wherein the unit sensors are configured to measure at least oneparameter selected from a group consisting of user set O₂ flow, exit O₂flow, exit O₂ temperature, battery capacity, H₂O₂ reservoir level,reaction chamber pressure, and/or water tank capacity (e.g., weight).

It is another aspect to provide a device as presented in any of theabove, wherein the unit control is configured to control at least oneparameter selected from a group consisting of peristaltic pump RPM,cooling fan speed, and water tank drainage solenoid. The control unitmay also comprise feedback circuits for one or more of the parameters asdisclosed in any of the above.

It is another aspect to provide a device as presented in any of theabove, wherein the control unit is configured to emit an alert in thecase of one or more of:

-   -   a. low H₂O₂ reservoir;    -   b. low battery;    -   c. high water tank level;    -   d. high device pressure;    -   e. oxygen purity; and    -   f. device maintenance.

It is another aspect to provide a device as presented in any of theabove, in which the control unit additionally comprises a data logger,the data logger configured to record the status of the device. Thecontrol unit may be configured to communicate with an external system,the communication selected characterized as:

-   -   a. transfer recorded data to an external system;    -   b. receiving treatment protocol from an external system.

It is another aspect to provide a device that is powered by a batteryunit, e.g., the battery may be a 12-18V/4-5 Ah Rechargeable.

It is another aspect to provide a device as presented in any of theabove, wherein the device additionally comprises a Biofeedback sensor.The biofeedback sensor may be configured to detect the peripheral bloodO₂ saturation level in the patient. The sensor may be configured tocommunicate with the control unit as disclosed above. For example, thesensor and the control unit may be configured to emit an alert in thecase of low or high O₂ patient saturation levels.

It is an aspect of this disclosure to provide a method for generatingoxygen, comprising steps of:

-   -   a. combining a hydrogen peroxide solution with a catalyst;    -   b. cooling the oxygen and water vapor;    -   c. draining liquid water, the water condensed from the water        vapor;    -   d. optionally, filtering oxygen, removing water; and    -   e. optionally, passing oxygen through a flow regulator.

It is another aspect to provide a method as presented in any of theabove, wherein the method additionally comprises a step of controlling aflow of the hydrogen peroxide solution into a reactor.

It is another aspect to provide a method as presented in any of theabove, wherein the method additionally comprises passing oxygen andwater vapor through an optional catalytic filter.

It is another aspect to provide a method as presented in any of theabove, wherein the step of cooling the oxygen and water vapor using acooling and/or condensing unit, wherein the cooling is provided at leastin part by generating a stream of air, the air generated by a fan, overat least a portion of the cooling and/or condensing unit.

It is another aspect to provide a method as presented in any of theabove, wherein the method additionally comprises a step of analyzing theoxygen flow and temperature of oxygen exiting the cooling system.

It is another aspect to provide a method as presented in any of theabove, wherein the method additionally comprises a step of alerting theuser in the case of one or more of low H₂O₂ reservoir, low battery, highsystem pressure, high water tank level, oxygen purity, and/or lowpatient O₂ saturation levels.

It is another aspect to provide a method as presented in any of theabove, wherein the method further comprises steps of:

-   -   a. providing oxygen to a patient; or    -   b. storing the oxygen.

It is another aspect to provide a method as presented in any of theabove, wherein the method additionally comprises a step of detecting theO₂ saturation levels in a patient.

It is another aspect to provide a method as presented in any of theabove, wherein the method additionally comprises one or more of:

-   -   a. logging the data of the device;    -   b. logging the data of the patient;    -   c. transferring the data to an external system.

It is another aspect to provide a method as presented in any of theabove, wherein the method additionally comprises steps of regulating theoxygen flow rate, the regulation controlled by regulating at least oneparameter selected from a group consisting of flow of the hydrogenperoxide solution into a reactor and flow via the flow regulator, theflow regulation determined by at least one parameter selected from agroup consisting of system pressure, reactor pressure, oxygen flow andpatient O₂ saturation level. It is another aspect to provide a method aspresented in any of the above, wherein the step of regulating the oxygenflow rate comprises a step of measuring the oxygen flow rate.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic representation of the portable chemical oxygengenerator according to this disclosure.

FIG. 2 depicts an embodiment of the portable chemical oxygen generatoraccording to the present disclosure.

FIG. 3 depicts an embodiment of the cooling system according to thisdisclosure.

FIG. 4 depicts an embodiment of the heat sink system according to thisdisclosure.

FIG. 5A shows an embodiment of the cooling enclosure that comprisesconsecutive U-bends having drainage ports at the lower portion of eachlower U-bend for the drainage of liquid (water) that has condensed inthe cooling enclosure. FIG. 5B shows an embodiment of the coolingenclosure that comprises a horizontal coil-shaped cooling enclosure, inwhich the drainage ports are situated at the lowest portion of each coilrotation.

FIG. 6 depicts an embodiment of the cooling system according to thisdisclosure.

FIG. 7 depicts an embodiment of the portable chemical oxygen generatoraccording to the present disclosure.

FIG. 8 shows the influence of the gas flow on the drained liquid fromeach outlet.

FIG. 9 shows the influence of the gas flow on the temperature of thedrained liquid.

FIG. 10 shows the influence of the gas flow on the heat released by thecooling system.

FIG. 11 shows the influence of the gas flow and the catalyst amount onthe drained liquid.

FIG. 12 shows the influence of the gas flow and the catalyst amount onthe drained liquid temperature.

FIG. 13 shows the influence of the gas flow and the catalyst amount onthe heat release.

DETAILED DESCRIPTION OF THE INVENTION

The chemical oxygen generator according to this disclosure is a devicethat produces oxygen though a chemical reaction. The chemical oxygengenerator is important for providing emergency oxygen in situations inwhich other methods such as oxygen tanks or electrolysis are notfeasible.

The chemical oxygen generator is used for supplementing and increasingthe concentration of oxygen in the inhaled air of a patient. Suchgaseous oxygen has a multitude of indications in which oxygensupplementation may be needed, including blood circulation problems (forexample due to illness or due to injury), breathing problems, decreasedlung function, and altitude sickness. Hypoxemia (insufficient oxygen inthe blood) is a common complication in acute lower respiratory tractinfections, such as pneumonia due to bacteria (Streptococcus pneumoniaeand Haemophilus influenzae) and viruses (respiratory syncytial virus,influenza virus, corona virus), and is a strong risk factor for death.

Other uses can be anywhere a compact and portable oxygen generator isneeded, such as in military operations, and third-world clinics. Thechemical oxygen generator may also be used in submarines, aircraft, andby firefighters and mine rescue crews.

Advantageously, the chemical oxygen generator according to thisdisclosure is compact and portable, yet is also reliable and simple tooperate. This chemical oxygen generator provides a controlled oxygenflow and temperature over an extended period of time. The flow of oxygenmay be controlled by the user to dispense from 0 L/min up to about 8L/min of oxygen gas, or up to about 10 L/min, or up to about 15 L/min.

The device can produce a sustained and controllable flow of breathableoxygen, substantially free of hydrogen peroxide and other contaminants.The term “substantially free” as used herein refers to concentrations ofhydrogen peroxide or other contaminants which are below medicallyacceptable levels, and accordingly do not present a risk of injury ordiscomfort to the patient. For example, the chemical oxygen generatordisclosed herein provides a flow of oxygen to the patient that has lessthan about 1 ppm of hydrogen peroxide, or less than about 0.5 ppm ofhydrogen peroxide. In some aspects, the present device can generate aconstant flow of oxygen up to about 8 L/min, or up to about 10 L/min, orup to about 15 L/min, at a temperature of less than about 40° C. formore than about 30 minutes.

Importantly, the chemical oxygen generator disclosed herein provides aflow of oxygen that is humidified and does not require the use of anexternal humidification apparatus. Humidified oxygen provides improvedpatient comfort and safety. Higher flow rates of oxygen without properhumidification may cause drying of the nasal or oral mucosa, withassociated bleeding and possible airway obstruction. For patient with anasopharyngeal catheter, an endotracheal tube or a tracheostomy,humidification of the supplied oxygen is important to keep secretionsthin and to avoid mucous plugs. Endotracheal tube obstruction due toinadequate humidification of supplied oxygen has been reported as thecause of many unnecessary deaths in hospitals. The chemical oxygengenerator disclosed herein addresses these concerns by suppling a flowof oxygen that is humidified.

Because the decomposition of hydrogen peroxide is highly exothermic, theoxygen produced in the reaction chamber may be at a temperature above90° C., and up to about 98° C., and thus is too hot for dispensing tothe patient. Using the chemical oxygen generator described herein, theoxygen exits the device, typically by way of flexible tubing fordelivery to the patient, at a comfortably breathable temperature, i.e.,below about 40° C. Advantageously, the oxygen that exits the device isnot more than about 10° C. above the ambient temperature (e.g., roomtemperature), or is not more than about 8° C. above the ambienttemperature, or is not more than about 6° C. above the ambienttemperature.

The portable oxygen generating system comprises a reaction chamber, afeed system for providing and controlling hydrogen peroxide solution tothe reaction chamber, and a cooling/condensing system for cooling thehot oxygen and water vapor leaving the reactor and condensing andremoving water. The reaction chamber comprises a catalyst thatfacilitates the chemical decomposition of hydrogen peroxide to oxygenand water, an inlet for the introduction of hydrogen peroxide solutioninto the reaction chamber, and an outlet for the release of oxygen andwater vapor from the reaction chamber. The hydrogen peroxide feed systemcomprises a hydrogen peroxide reservoir that contains aqueous hydrogenperoxide solution and a feed flow regulator for controlling the rate ofaddition of the aqueous hydrogen peroxide solution into the reactionchamber. The cooling system comprises an inlet for receiving oxygen andwater vapor, a condenser comprising two or more drains, each configuredto drain water condensed from the water vapor in the cooling system, andan outlet for the release of cooled oxygen gas with reduced water vapor.

Oxygen Source

The oxygen source for the chemical generation of oxygen is hydrogenperoxide, or is an adduct or complex of hydrogen peroxide. An aqueoussolution of hydrogen peroxide is preferred for use as the oxygen sourcein the chemical reaction used in the devices provided herein.

The general reaction for the hydrogen peroxide decomposition used in thereactor to provide the formation of oxygen gas is:2H₂O₂→O₂+2H₂O

Hydrogen peroxide is commonly available as a water solution, withconcentrations ranging from 3% up to 70%. The concentration of H₂O₂ ispreferably at least 20%, and may be from about 30% to about 70%.

Catalyst

The reaction chamber contains a catalyst that facilitates the exothermicdecomposition of hydrogen peroxide. The catalyst may comprise a metal, ametalloid, an alloy of a metal, an alloy of a metalloid, a compound of ametal, such as a metal oxide, and a compound of a metalloid, or mixturesthereof. The catalyst may comprise transition metal oxides such as MnO₂,PbO₂, Co₃O₄, V₂O₅, KMnO₄, silver-based catalysts, Ni-based catalysts,Fe-based catalysts, Pt-based catalysts, Pd-based catalysts. Metalcatalyst may comprise one or more of silver, gold, zinc, platinum,palladium, or other metal catalyst. Alternatively, an acid may be usedto catalyze the reaction.

When a solid heterogeneous catalysts in used (i.e., a catalyst that isinsoluble in water), the production of oxygen occurs at the surface ofthe catalyst. Solid heterogeneous catalysts may be selected from thecatalysts listed above and which are not soluble in water. Solidheterogeneous catalysts have the advantage that they can be reused manytimes with new portions of hydrogen peroxide, while maintaining highefficiency.

The catalyst may be in the form of a powder or a granulate. Catalysts inpowder form may have relatively faster kinetics because of the largersurface area. However, a granulate may be more convenient to handle andto reuse. Although the high surface area of powdered catalysts helps toensure a rapid decomposition of the hydrogen peroxide, fine powders maypresent issues in retaining the catalyst in the reaction chamber.

The catalyst may be in the form of a granulate, for example having adiameter of about 0.5 mm to about 5 mm. The catalyst granulate maycomprise one or more of the metal, metalloid, alloy of a metal, alloy ofa metalloid, a compound of a metal, or a compound of a metalloid. Thegranulate may further comprise one or more binder materials.

The catalyst may be dispersed or coated on the surface of a solidsupport material, or matrix. Alternatively, the catalyst may impregnatedin in inert matrix material or binder.

The catalyst may comprise a porous matrix, for example, a porousscaffold structure onto which nano-particles of the catalyst aredeposited. The porous matrix or scaffold structure can be formed frommany suitable materials or combinations of materials. Non-limitingexamples of suitable materials include organic materials or inorganicmaterials, and may include a resins, polymers, metal, glass, ceramic,activated carbon, textiles, or a combination thereof.

The porous matrix or scaffold structure may be formed of a polymersponge. The polymer matrix/support should be selected from materialsthat can withstand the high concentration of hydrogen peroxide and hightemperature in the reactor, and may include, for example,polycarbonates, PVC, high-density polyethylene. The porous scaffoldstructure may be formed by a synthesis of a poly-High Internal PhaseEmulsion (poly-HIPE) method. The polymerization of the continuous phaseof HIPEs leads to the formation of porous polymer monoliths, calledpolyHIPEs. The polyHIPEs have a high porosity with voids sizes of about10-100 μm.

In some aspects, the porous scaffold structure may be formed by granularporous materials. For example, granules of porous material, representinga support of the porous scaffold structure, may be held together to formthe porous scaffold structure. A variety of granular porous materialsmay be used including, but not limited to, activated carbon, polymerbeads, silica sand, zirconia, alumina, anthracite, and the like.

Multiple variables may affect the oxygen release rate including the rateof addition of hydrogen peroxide, the temperature of the reactionchamber, and the amount of catalyst in contact with the hydrogenperoxide solution. The catalyst may be eliminated as a variable byensuring that the reaction chamber contains excess catalyst relative tothe hydrogen peroxide introduced into the reaction chamber. Once thereaction is under way, the temperature of the reaction chamber ismaintained at or above about 90° C., and up to about 98° C., whileoxygen is being produced. With a sufficient amount of solid catalyst(such as manganese dioxide) present in the reaction chamber, the rate ofoxygen production may be controlled by the rate of addition of theaqueous hydrogen peroxide solution to the reaction chamber. It istherefore an aspect to produce oxygen at a controllable and selectivelyconstant rate.

H₂O₂ Reservoir

A reservoir holds the hydrogen peroxide solution. The reservoir isconstructed from inert, non-reactive materials such as stainless steelor polymers/plastics. The reservoir can be a single use or disposablecontainer, or can be refillable. The reservoir may be a cartridge thatholds the hydrogen peroxide solution that is fed into the reactionchamber by the feed flow regulator. In some embodiments, the reservoiris part of the system and is refiled from another container.

The reservoir can be hard or soft-sided. In some embodiments, thereservoir may be constructed like a ‘syringe’ i.e. is constructed from abarrel and a plunger (or piston).

In some embodiments, the reservoir is a canister capable of holding asolution of hydrogen peroxide in water that is sufficient to maintain asteady flow of oxygen for at least about 20 minutes, or at least about30 minutes, at an oxygen flow rate of about 8 L/min, or about 10 L/min,or about 15 L/min. The concentration of hydrogen peroxide is at leastabout 15%, or at least about 20%. The concentration of hydrogen peroxidemay be from about 30% to about 70%. The hydrogen peroxide reservoir mayhold from about 500 ml to about 4000 ml of hydrogen peroxide solution,or from about 1000 ml to about 3000 ml of hydrogen peroxide solution.

Feed Flow Regulator

The rate of hydrogen peroxide solution that is provided to the reactionchamber by the feed system may be controlled by the user in order tomaintain the desired oxygen flow. In some embodiments the feed flowregulator comprises, a pump to controls the flow of the hydrogenperoxide solution into the reactor. The pump may be any suitable pumpingunit known in the art, including but not limited to, a displacementpump, peristaltic pump, syringe pump, piston pump, plunger pump, screwpump or reciprocating pump. In some embodiments, the reservoir may becollapsible and the feeding unit is configured to put pressure on thereservoir, thereby pushing the hydrogen peroxide solution into thereactor. In some embodiments, the feeding unit acts as a reciprocatingpump with the reservoir forming part of the pump.

Reactor

The reaction chamber comprises a pressure tight housing in which occursthe chemical decomposition of the oxygen source, typically hydrogenperoxide as an aqueous solution. The reaction chamber comprises thecatalyst that facilitates the chemical decomposition of hydrogenperoxide to oxygen and water, an inlet for the introduction of hydrogenperoxide solution into the reaction chamber, and an outlet for therelease of oxygen and water vapor from the reaction chamber.

The reaction chamber may optionally comprise an overpressure valve toprevent a housing rupture, for example, in the event the oxygen outletis occluded. The pressure valve may be configured to regulate thepressure in the reaction chamber by releasing excess gas and/or byregulating the feed solution flow rate. Regulation of the flow rate bythe pressure valve can be conducted directly or by the control unit.

The reactor outlet may optionally comprise a filter or mesh, whichfunctions to maintain the catalyst in the reaction chamber. Such afilter or mesh may be particularly useful in the event that the catalystis powder and has a small particle size.

The reaction chamber is constructed from an inert, non-reactive materialthat can withstand temperatures of at least 100° C. The reactor may beconstructed of an inert/nonreactive metal or metal alloy includingaluminum, stainless steel, nickel alloys such as Inconel, and the like.Alternatively, the reaction chamber may be constructed of aninert/nonreactive polymeric material. In the present context, inert ornon-reactive materials are those that do not degrade under the reactionconditions. However, in some embodiments, the material selected for thereaction chamber, and which contacts the hydrogen peroxide, may catalyzethe decomposition of the hydrogen peroxide.

The aqueous hydrogen peroxide solution enters the reactor from thefeeding unit through at least one aperture or inlet, such as a nozzle ora spray nozzle. The solution mixes with the catalyst, rapidlydecomposing the H₂O₂ to H₂O and O₂. The reaction is exothermic, reachingsustained temperatures above 90° C., and up to about 98° C., andaccordingly water is vaporized to steam in the reactor. The gas producedby the decomposition of hydrogen peroxide flows out of the reactor fromthe reactor outlet. Optionally, the reaction chamber may also comprise adrain that allow for the removal of any accumulated liquid water. Theflow of the gaseous reaction products (O₂, H₂O) out of the reactionchamber is directly proportional to the rate at which the hydrogenperoxide solution is pumped into the reactor.

Catalytic Filter

Exiting the reaction chamber are the reaction products, oxygen and watervapor, and in some embodiments, some unreacted liquid or gaseoushydrogen peroxide. In the event that some hydrogen peroxide exits thereaction chamber, the oxygen generator may optionally comprise asecondary reactor, termed a catalytic filter, that provides for thedecomposition of the residual hydrogen peroxide.

The catalytic filter is constructed to decompose any hydrogen peroxidethat has been vaporized or distilled by the decomposition reaction andexited the reaction chamber. The catalytic filter contains one or morecatalysts that facilitate the decomposition of hydrogen peroxide intooxygen and water, as discussed above. The catalytic filter may containof the same catalyst as the reactor or of another catalyst. The gas flowexiting the catalytic filter may be substantially free of hydrogenperoxide, and accordingly hydrogen peroxide in the exiting gas flow isat or below medically acceptable levels.

Cooling Unit/Condenser

The disclosure provides a cooling unit or system for the cooling andseparating of a gaseous mixture. Although the cooling system isdescribed for use in cooling and separating water from oxygen gas, thecooling system may be adapted for the cooling and separating of othermixtures.

The hot mixture that enters the cooling unit comprises a mixture of atleast two components, a low boiling component and a high boilingcomponent. In the case of the oxygen generator, the low boilingcomponent is oxygen and the high boiling component is water. The hotvapor flows into the condensing/cooling unit. The condensing/coolingunit comprises an enclosure, configured to contain and cool thegas/vapor mixture, thereby converting the condensable vapor into liquid.In some embodiments, the enclosure is piping or tubing. The condensingenclosure comprises at least one drain throughout the length of theunit, and preferable a plurality of drains, enabling the condensedliquid to be separated from gas flow and drained into a tank. In someembodiments, the cooling enclosure comprises a plurality of drains,enabling draining of condensed liquid throughout the length of thecooling unit, allowing the liquid to be separated by rapid andcontinuously draining.

For the oxygen generator described herein, hot gasses exiting thereaction chamber or the catalytic filter, if present, are passed into acooling unit. The gas flow entering the cooling unit may be above about90° C., and up to about 98° C., and thus is too hot for dispensing tothe patient. The cooling unit cools the gas flow to a comfortablybreathable temperature, i.e., below about 40° C.

The cooling unit is configured to cool the gas flow, condensing thewater vapor into liquid water, and removing the liquid water. Thecooling unit allows the liquid water to be separated from the gas flowand drained into a storage tank. In some aspects, the cooling unitprovides draining throughout the length of the cooling unit allowing theliquid water to be drained rapidly and continuously. This system rapidlyremoves the condensed water, which may be at elevated temperature, asits condensation takes place. By removing the water from the systemthroughout the length of the cooling enclosure, the cooling capacity ofthe cooling system may be directed to the efficient cooling of theoxygen gas flow, without having to fully cool the condensing water. Thisarrangement directs the cooling capacity of the cooling system towardscooling the lower mass oxygen flow, increasing the efficiency of thecooling.

In one embodiment, the cooling enclosure is formed of vertical sectionsof pipe connected by U-bends. When the device is in operation, the lowerU-bends of the cooling system are horizontally situated with drainageports at the lowest points along the pipe, allowing gravity to assist inthe continuous drainage of the condensed liquid water from the coolingsystem. Alternatively, the cooling enclosure may comprises pipecontaining the gas flow in the form of a horizontal coil, havingdrainage ports situated along the lowest points for each coil rotation.The cooling enclosure may be incorporated into a heat sink and/or mayhave cooling fins along the outside of the enclosure. A cooling fluidmay be directed past the cooling enclosure to assist in the removal ofheat from the cooling enclosure. The cooling fluid may be a liquid or agas, and in some embodiments is a flow of cooling air.

In preferred aspects, the cooling system is an active air coolingsystem. An electric fan may be used as the active component of thecooling system. The cooling air is generated by the fan passes andaround the enclosure, cooling the body of the enclosure. Cooled oxygenexits condensing enclosure via the exhaust/exit tube. Advantageously,the oxygen that exits the cooling system is not more than about 10° C.above the ambient temperature, or is not more than about 8° C. above theambient temperature, or is not more than about 6° C. above the ambienttemperature.

Hydrophobic Membrane

In embodiments, humid oxygen gas exiting the cooling system passesthrough a hydrophobic membrane, filtering traces of water. Liquid watercan interfere with the accuracy of measuring the oxygen flow. Thehydrophobic membrane is a microporous membrane of polymeric material.The hydrophobic membrane may be constructed from any material known inthe art for this purpose, including acrylic co-polymers,polytetrafluoroethylene (PTFE), polyvinylidenedifluoride (PVDF),polysulfones and polycarbonates. Commercially available as ventilationplugs having a hydrophobic membrane may be used for this purpose.

In embodiments, a drier may be situated between the reaction chamber, orthe catalytic filter if present, and the cooling system. The driercomprises a hydrophobic membrane and serves to remove a portion of thewater from the gas flow prior to the flow entering the cooling system.The drier may remove up to about 90% of the water from the gas flow, orfrom about 70% to about 90% of the water from the gas flow. Removing aportion of the water prior to the gas flow entering the cooling systemmay increase the efficiency of the cooling system. The hydrophobicmembrane is a microporous membrane of polymeric material and may beconstructed from any material known in the art for this purpose,including acrylic co-polymers, polytetrafluoroethylene (PTFE),polyvinylidenedifluoride (PVDF).

FIG. 1 schematically shows the basic unit 10 of an embodiment of thechemical oxygen generator. The reservoir 11 holds the hydrogen peroxidesolution. The holder can be single use or refillable. In someembodiments, the reservoir is a cartridge that holds the solution and isfed into the system. In some embodiments, the reservoir is part of thesystem and is refilled from another container. The reservoir can be hardor soft-sided. The reservoir is constructed from inert, non-reactive,medicinal grade materials. In some embodiments, the reservoir isconstricted like a ‘syringe’ i.e. is constructed from a barrel and aplunger (or piston). In some embodiments the reservoir is a canistercapable of holding a solution of hydrogen peroxide (H₂O₂) in water. Thepercentage of hydrogen peroxide is at least 20% and in some embodimentsis 30-70%.

The feeding unit 12 controls the flow of the hydrogen peroxide solutioninto the reactor. In some embodiments, the feeding unit is a pump. Thepump can be, for example, a displacement pump, peristaltic pump, syringepump, piston pump, plunger pump, screw pump or reciprocating pump. Insome embodiments, the reservoir 12 is collapsible and the feeding unitis configured to put pressure on the reservoir, pushing the hydrogenperoxide solution into the reactor. In some embodiments, the feedingunit acts as a reciprocating pump with the reservoir forming part of thepump.

The feeding unit can be set to control the flow rate according tovarious parameters including: hydrogen peroxide solution flow rate,oxygen flow rate (at the exit of the device), and reaction chamberpressure. In some embodiments, the feeding unit additionally comprises apressure sensor.

The reaction chamber 13 comprises the catalyst that facilitates thechemical decomposition of hydrogen peroxide to oxygen and water, aninlet for the introduction of hydrogen peroxide solution into thereaction chamber, and an outlet for the release of oxygen and watervapor from the reaction chamber. The reaction chamber is constructedfrom an inert, non-reactive material that can withstand temperatures ofat least 100° C.

The aqueous hydrogen peroxide solution enters the reactor from thefeeding unit through at least one aperture or inlet, such as a nozzle ora spray nozzle. The reactor contains the catalyst that catalyzes thedecomposition of hydrogen peroxide to water and oxygen. The solutionmixes with the solid catalyst particles, decomposing the hydrogenperoxide to H₂O and O₂. The reaction is exothermic, reachingtemperatures above 90, and up to about 98° C. The gas produced by thedecomposition of hydrogen peroxide flows out of the reactor and throughthe catalytic filter 14.

The reaction chamber can additionally comprise a pressure valve. In someembodiments the pressure valve is configured to regulate the pressure inthe reaction chamber by releasing excess gas or by regulating thesolution flow rate. Regulation of the flow rate by the pressure valvecan be conducted directly or by the control unit.

The catalytic filter 14 is constructed to decompose any hydrogenperoxide that has been vaporized or distilled by the decompositionreaction. The filter can be constructed of the same catalyst as presentin the reactor or of another catalyst.

Gas that flows through the filter 14 passes into a cooling unit 15. Thecooling unit is configured to cool the gas, condensing the water vaporinto liquid water. The cooling unit enables the liquid to be drainedinto a tank. In some embodiments, the cooling unit provide drainingthroughout the length of the cooling unit. In some embodiments, theliquid is drained instantly and continuously. The water tank holds thewater and can be drained.

Gas that passes through the cooling unit 15 passes through a hydrophobicmembrane (or filter) 16 to remove any water vapor that was not condensedthroughout the cooling unit.

An oxygen flow regulator 17 comprises a flow meter that measures theamount of oxygen that passes the filter 16. The flow meter may regulatethe feeding unit to ensure that the flow of oxygen is continuous and atthe required level. The flow regulator can also measure the temperatureof the gas to make sure that the oxygen is not too hot for the patient.In some embodiments, the flow regulator additionally comprises a valvefor regulating the oxygen flow. The valve can be manual, mechanical orelectro-mechanical. In some embodiments the valve is controlled by theuser, the control unit or directly by the flow meter.

The system contains a Control and Display unit and power source 18. Adisplay unit can display all of the critical device parameters: oxygenflow, oxygen temperature, water tank content level, reservoir level,system pressure, battery power level etc. The control and display unitcan also track the overall status of the system, such as usage status,catalyst status, maintenance etc.

In some embodiments, the system additionally comprises a biosensor. Insome embodiments, the biosensor is an O2 blood saturation sensor that isconnected to a patient. The sensor can be connected to the control unitto track the saturation level of the patient. In some embodiments, thecontrol unit is configured to control the Oxygen flow rate according tothe O2 saturation level of the patient. The control unit can control theoxygen rate by regulating the exit valve or the feeding unit.

The system contains an exit port 19 through which the final oxygenproduced exits the device and can then be delivered to a patient orstored for later use.

Reference is now made to FIG. 2, which depicts a specific embodiment ofthe oxygen generating device.

The oxygen generating device 20, comprises a hydrogen peroxide cartridge21 containing the hydrogen peroxide solution (for example 50%-60%),which is the substrate of the chemical reaction, producing H₂O and O₂.The cartridge volume may be 750-3000 ml, sufficient to produce a flow of10 L/min O₂ for 30-45 min. The cartridge is designed to be rapidlyreplaceable once it gets empty, enabling continues flow of oxygen.

A pump 22, such as peristaltic pump, drives the hydrogen peroxidesolution from the cartridge 21 to the reaction chamber 23, where thechemical reaction takes place. The pump speed (RPM) is controlledthrough the control unit.

The hydrogen peroxide is fed into the reaction chamber 23, mixing withthe solid catalyst particles, and decomposing the hydrogen peroxide towater and oxygen. The reaction is exothermic, reaching temperaturesabove about 90° C., and up to 98° C., and creating a constant Power upto 1,500 W.

Exiting the reaction chamber are oxygen, water as steam, and some liquidand gaseous hydrogen peroxide. The flow of the reaction products (O₂,H₂O) is directly proportional to the pump RPM (the reaction is saturatedwith catalyst). A pressure gauge 24 a tracks the pressure in thereaction chamber. In cases of excess pressure, a pressure valve 24 b canrelease excess gas.

The mixture exiting the reaction chamber is directed into a catalyticfilter 25, packed with catalytic particles. Traces of hydrogen peroxide(liquid or gaseous) are chemically decomposed to oxygen and water,preventing any corrosive hydrogen peroxide from reaching the patient.

The hot oxygen and steam exiting the catalytic filter 25 flows into anactive air cooling system comprising a fan 26 a and a cooling enclosure26 b. While going through the system, condensation takes place, water ispouring down through ports at the bottom of each curve within thecooling enclosure. This arrangement efficiently directs the coolingcapacity towards low mass steam condensation, rather than cooling highmass water. An electric fan 26 b (60 W) is used as the active componentof the cooling system.

Water is collected into a water tank 27, and drained out timely througha solenoid controlled tap.

Humid oxygen exiting the cooling system flows through a hydrophobicmembrane 28, filtering additional water. Liquid within the O₂ pipe caninterfere with accurately measuring the O₂ flow.

A heat meter 29 a and mass oxygen flow meter 29 b are used for real-timeflow measurement of the oxygen exiting the device through exit port 29c.

Reference is now made to FIG. 3, providing a cross-section of a coolingsystem 30. The cooling air is generated by a fan 31 and funneled 32 toan area 33 surrounding the pipe 34 containing the oxygen and water vaporgenerated by the reactor. The gas stream is then de-humidified by ahydrophobic membrane 35 before exiting the system through port 36, to beprovided to a patient.

Reference is now made to FIG. 4 describing a heat sink cooling system40. The mixture of hot oxygen and water vapor enters the sink through41. As the gas is cooled, and the water vapor is converted to liquid,the liquid water is drained through the drainage ports 42 at the lowestposition of the U-bends 44, such that the content of water in the oxygenthat exits the system through 43 is reduced. FIG. 4 presents the coolingunit of FIG. 3 at a 90° rotation on the Y-axis (i.e., a side view).

Reference is now made to FIG. 5, which shows representative embodimentof the cooling enclosure of the cooling system. FIG. 5A shows a coolingenclosure that comprises consecutive U-bends. At the lowest portion ofeach lower U-bend 51, there is a drainage port 52 for the drainage ofliquid (water) that has condensed in the cooling enclosure. FIG. 5Bshows a horizontal coil-shaped cooling enclosure, in which the drainageports 52 are situated at the lowest portion of each coil rotation.

Reference is now made to FIG. 6, which shows a representative embodimentof the cooling system. The hot gaseous mixture, (such as hot oxygen andsteam) flows into an active air cooling system 60 comprising a fan 66 aand a cooling enclosure 66 b. While going through the system,condensation takes place, the lower boiling component (such as water)condenses and drains down through the drainage ports 66 e at the bottomof each lower U-bend 66 d within the cooling enclosure. This arrangementefficiently directs the cooling capacity towards a reduced mass streamcomprising the lower boing component (such as oxygen), rather thancooling high mass of the condensed higher boiling component (such aswater). An electric fan 66 b is used as the active component of thecooling system. The higher boiling component (such as water) iscollected into a tank 67.

Reference is now made to FIG. 7, which depicts a specific embodiment ofthe oxygen generating device. The oxygen generating device 70, comprisesa hydrogen peroxide cartridge 71 containing the hydrogen peroxidesolution (for example 50%-60%), which is the substrate of the chemicalreaction, producing H₂O and O₂. The cartridge volume may be 750-3000 ml,sufficient to produce a flow of 10 l/min O₂ or more for 30-45 min. Thecartridge is designed to be instantly replaceable once it gets empty,enabling continues flow of oxygen.

A pump 72, such as peristaltic pump, drives the hydrogen peroxidesolution from the cartridge 71 to the reaction chamber 73, where thechemical reaction takes place. The pump speed (RPM) is controlledthrough the control unit 79 d.

The hydrogen peroxide is fed into the reaction chamber 73, mixing withthe solid catalyst particles, and decomposing the hydrogen peroxide towater and oxygen. The reaction is exothermic, reaching temperaturesabove about 90° C., and up to 98° C.

Exiting the reaction chamber are oxygen, water as steam, and some liquidand gaseous hydrogen peroxide. The flow of the reaction products (O₂,H₂O) is directly proportional to the pump RPM (the reaction is saturatedwith catalyst). A pressure gauge 74 a tracks the pressure in thereaction chamber. In cases of excess pressure, a pressure valve 74 b canrelease excess gas.

The mixture exiting the reaction chamber is directed into a catalyticfilter 75, packed with catalytic particles. Traces of hydrogen peroxide(liquid or gaseous) are chemically decomposed to oxygen and water,preventing any corrosive hydrogen peroxide from reaching the patient.

The hot oxygen and steam exiting the catalytic filter 75 flows into adrier 76 c which comprises a hydrophobic membrane and serves to remove aportion of the water from the gas flow prior to the flow entering thecooling system.

The partially dried hot oxygen and water vapor flows into an active aircooling system comprising a fan 76 a and a cooling enclosure 76 b. Whilegoing through the system, condensation takes place and liquid waterdrains down through the drainage ports at the bottom of each lowerU-bend within the cooling enclosure. The water is collected into a watertank 77, and drained out through a solenoid controlled tap.

Liquid within the O₂ pipe can interfere with accurately measuring the O₂flow. Humid oxygen exiting the cooling system flows through ahydrophobic membrane 78, filtering additional water. Any water may bedrained from the hydrophobic membrane through the drainage 78 a.Optionally, the oxygen flow exiting the hydrophobic filter passesthrough an additional drying filter 78 b comprising a desiccating agentsuch as silica.

A temperature gauge 79 a and mass oxygen flow meter 79 b are used forreal-time flow measurement of the oxygen exiting the device through exitport 79 c.

The device is powered by a battery unit 79 e, which may comprise arechargeable 12-18V/4-5 Ah battery. The device additionally comprises anelectronic control and display unit 79 d. The control and display unit79 d may be configured to control parameters selected from pump RPM,cooling fan speed, and water tank drainage. The control unit may alsocomprise feedback circuits for one or more of the parameters asdisclosed in any of the above. The control unit may be configured tomonitor and/or emit an alert in the case of one or more of low H₂O₂reservoir, low battery, high water tank level, high device pressure,oxygen purity, and device maintenance.

Examples

Materials and Methods

The cooling system performance was tested by several parameters: drainedliquid mass and volume, drained liquid temperature and the heat releasedfrom each outlet point.

The data was collected during operation of the device for 5 minutesusing 50% of hydrogen peroxide (H₂O₂) and a catalyst for hydrogenperoxide decomposition (Hydrogen Link OxyCatalyst). The gas flow wasmeasured by a gas flow meter and was controlled indirectly, bycontrolling the hydrogen peroxide flow using a peristaltic pump.

The volume was measured by measuring cylinders, the mass was measured byan analytic balance. The temperature was measured by a thermometer(ExTech 4-channel thermometer, model SDL 200). The heat was calculatedusing the equation:Q=m·Cp·(T _(inlet) −T _(outlet))

Q=heat (cal.)

m=drained liquid mass (g)

${Cp} = {{heat}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu}{water}\mspace{14mu}( \frac{cal}{{g \cdot {^\circ}}\mspace{14mu}{C.}} )}$

T=drained liquid temperature (° C.)

T_(inlet)=reaction temperature, for the first outlet point;

T_(outlet) of the previous outlet point, for n>2 outlet point

Table 1 provides the parameters measured at the cooling system of theoxygen generator.

TABLE 1 Reaction Liquid Gas Heat Catalyst Gas Temp Vol. Mass Temp TempRelease Mass Flow (° C.) (ml) (g) (° C.) (° C.) (cal) 272 g 10 92.4outlet 1 131 126.83 60.5 23.8 4045.877 LPM outlet 2 71 68.68 50.7 25.4432.684 outlet 3 21 19.75 40 24.7 211.325 outlet 4 1.62 24.4 23.5 25.272136 g 10 92.4 outlet 1 180 175.47 60.6 25.3 5579.946 LPM outlet 2 6966.63 55.9 23.9 313.161 outlet 3 9.1 8.84 36.9 24.5 167.96 outlet 4 0 0272 g  7 96.1 outlet 1 112 108.48 57 22.7 4339.2 LPM outlet 2 24 22.4638.8 23.5 487.382 outlet 3 3.7 3.14 27.7 24.2 34.854 outlet 4 0 0 136 g 7 95.1 outlet 1 66 63.81 56.1 22.4 2488.59 LPM outlet 2 44 42.04 52.422.35 155.548 outlet 3 4.8 4.4 32.1 22.6 89.32 outlet 4 0 0 272 g  592.4 outlet 1 118 114.4 38.1 20.6 6211.92 LPM outlet 2 15 14.2086 25.720.9 176.18664 outlet 3 0.2 20 22.4 1.14 outlet 4 0 0 136 g  5 92.4outlet 1 85 82.9 45.8 22.7 3863.14 LPM outlet 2 19 17.68 27.7 22.3320.008 outlet 3 0 0 outlet 4 0 0

1.1 Effect of Gas Flow

Theoretically, increasing the gas flow requires increasing the hydrogenperoxide flow, which increases its decomposition reaction rate in thereaction chamber. Adding more reactants, hydrogen peroxide in this case,encourages the catalyst to catalyze the decomposition reaction. Thatleads to the production of more oxygen and water and increases thetemperature in the reaction chamber due to the production of heat fromthe exothermic reaction. Thus, as the hydrogen peroxide flow increasesand the amount of hydrogen peroxide entering the reaction chamberincreases, it is expected that the drained liquid mass and liquidtemperature will increase as more heat is released.

1.1.1 Drained Liquid Mass

The products of the hydrogen peroxide decomposition reaction are waterand oxygen. In the high flow experiments (7 and 10 LPM), traces ofhydrogen peroxide were found in the drained liquid at the first and thesecond outlet points. That indicates that not all the H₂O₂ reacted inthe reaction chamber and it was condensed in the cooling system. It canbe concluded that the amount of catalyst is to be increased tocompensate for the high flow of the H₂O₂.

FIG. 8 presents the liquid mass drained from the outlet points 1-4 at 5,7 and 10 LPM flow. As it can be seen, only for the high flow of 10 LPMthe 4th outlet point participated in the cooling process. In addition,the trend is the same for all three flows. The drained liquid massdecreases as the outlet point number increases. That can be explained bythe fact that most of the liquid is condensed in the first outlet pointdue to the high temperature difference (the gas stream has a temperatureof 92-96° C. as it goes out from the reaction chamber).

The graph of the 10 LPM is higher than the two others in a significantmanner, while the difference between the 5 and the 7 LPM is small.However, for the 7 LPM, higher total mass of liquid was drained from thecooling system (not significantly). Moreover, for the 7 LPM, the 3rdoutlet point participated in the cooling process while for the 5 LPMonly 2 outlet points were needed.

1.1.2 Drained Liquid Temperature

The temperature of the drained liquid indicates the efficiency of thecooling process at each outlet point. As presented in FIG. 9, for allthree flow rates, the temperature decreases as the outlet point numberincreases. Comparison between the different flows shows that at eachoutlet point the temperature decreases with the flow. The efficiency isthe highest for the 5 LPM and the lowest efficiency was obtained for the10 LPM. For the highest flow, the highest mass of products (water andoxygen) was produced. Thus, the cooling needed is “harder”. It isexpressed by higher temperature of the drained liquid and the numbers ofoutlet points needed for the cooling.

1.1.3 Heat Release

The heat released during the cooling process is calculated based on thedrained liquid mass and the temperatures difference between the inletand the outlet. This parameter, as the temperature, indicated theefficiency of the cooling. FIG. 10 shows the heat released from eachoutlet point at the different flows. The heat released at each outletpoint decreases as the point number increases since less mass isrequired to be cooled and the delta of the temperature gets smaller, sothere is less heat to release. This trend exists in all tested flows.The lowest flow of 5 LPM required the lowest hydrogen peroxide flow. Lowflow of reactant enabled the catalyst to more fully catalyze thehydrogen peroxide than in the other gas flow experiments and enabled thecooling system to evacuate more of the heat at the beginning of thecooling system. The high flow of hydrogen peroxide (as in the 7 and 10LPM experiments) cause an increase of high temperature gas to be cooled,thus the efficiency of the cooling is lower which is expressed in higherliquid temperature as shown in FIG. 9 and lower heat released presentedin FIG. 10.

1.2 Effect of Catalyst Amount

In general, chemical reactions occur faster in the presence of acatalyst because the catalyst provides an alternative reaction pathwaywith a lower activation energy than the non-catalyzed mechanism. Thus,the catalyst amount has a significant influence upon the reaction rate.It is expected to get a higher reaction rate for higher amount ofcatalyst up to the point that the catalyst is present in sufficientexcess.

1.2.1 Drained Liquid Mass

FIG. 11 presents the influence of the catalyst amount on the drainedliquid for different flows. In order to obtain a certain gas flow forthe same liquid flow (constant pump voltage) longer time was needed inthe low catalyst experiments (30 seconds in all low catalystexperiments). Because the overall experiment time was constant (5minutes), less drained liquid was obtained during that time from thefirst outlet point. For the second and the third outlets the trend wasopposite since less liquid was left to be condensed (most of the liquidwas condensed at the first outlet point). However, for high flow of 10LPM, for the low catalyst amount, higher mass of liquid was drained fromall the outlets points compared to the high amount. That can beexplained by the “overloading phenomenon” that was observed in the highflow experiment. As been explained in section 1.1.1, 10 LPM was found tobe too high flow for that reaction chamber design. That causes to anoverloading the reaction chamber with hydrogen peroxide while thecatalyst cannot catalyze it on the same rate. The result of the“overloading phenomenon” is incomplete reaction and presence of hydrogenperoxide in the drained liquid. That phenomenon is stronger for the highflow (10 LPM) low catalyst experiment. It means that more hydrogenperoxide is drained than compared to the high catalyst experiments.Since hydrogen peroxide is denser than water, the drained liquid massfor the low catalyst amount is higher.

1.2.2 Drained Liquid Temperature

The results for the temperature are presented in FIG. 12 and showsdominant behavior—the higher temperatures obtained for the lowercatalyst amount for a certain flow. That is expected since the mass ofdrained liquid is lower. That means less energy is released through thecondensing process, and it leads to higher temperatures. However, the 10LPM shows not consistent behavior. For the first outlet point the lowcatalyst has almost the same liquid drained temperature, for the secondoutlet the low catalyst has higher liquid drained temperature and forthe third one the high catalyst caused to higher temperature. Again, theoverloading prevented from some of the hydrogen peroxide to react in thereaction chamber, and it is reasonable to assume that some of thereaction occurred in the cooling system, thus no conclusions can be madebased on the temperature results.

Comparing the different flows can show that decreasing the flow,decreases the temperature at each outlet point, for each catalystamount, since more liquid was condensed and by that consumed more of thereleased heat for the condensing process which is an endothermic.

1.2.3 Heat Release

Looking at the heat release results presented in FIG. 13 show thatincreasing the flow decreases the heat released from each outlet foreach catalyst amount (except for the 10 LPM which, as being explained,was overloaded). High heat released by the cooling system represent theefficiency of the cooling process. The best efficiency was obtained forthe lower flow at each catalyst amount since the delta of the inlet andoutlet temperatures was the biggest. Based on the Equation 1, the heatis calculated based on this temperatures difference. The trend for allthe experiments is the same—the heat released from each outlet pointdecreases dramatically between the first and the second outlet pointsand the slope becomes more moderate between the second and the thirdoutlets. This result proves that most of the heat releases in the firstoutlet point and it is the most efficient cooling point. Comparingbetween two catalyst amounts for the same flow (except the 10 LPM)reveals that for the higher catalyst amount the more heat release due tothe fact that higher amount catalyze the reaction better so higher massof products is obtained (while the pump voltage is constant) during theexperiment and higher heat is generated in this exothermic reaction.

The results show that the drained liquid mass decreases as the outletpoint number increases. For each flow rate, the drained liquidtemperature decreases as the outlet point number increases. At eachoutlet point, the temperature also decreases with the flow. The heatreleased at each outlet point decreases as the point number increases.For the highest flow rate, the highest mass of products (water andoxygen) was produced.

The efficiency is the highest for the 5 LPM and the lowest efficiencywas obtained for the 10 LPM. The best efficiency was obtained for thelower flow at each catalyst amount. The first outlet point is the mostefficient cooling point.

We claim:
 1. A portable oxygen generating device, comprising: a reactionchamber comprising: a catalyst that facilitates the chemicaldecomposition of hydrogen peroxide to oxygen and water, an inlet forintroduction of hydrogen peroxide solution into the reaction chamber,and an outlet for release of oxygen and water vapor from the reactionchamber; a hydrogen peroxide feed system in fluid communication with theinlet of the reaction chamber, comprising: a hydrogen peroxide reservoirthat contains aqueous hydrogen peroxide solution as a replaceablecartridge, and a feed flow regulator that controls a rate of addition ofthe aqueous hydrogen peroxide solution into the reaction chamber; acooling system, comprising: an inlet, in fluid communication with theoutlet of the reaction chamber, for receiving the oxygen and watervapor, and a condenser comprising two or more drains, each configured todrain water condensed from the water vapor in the cooling system; anoutlet for release of cooled oxygen gas with reduced water vapor; andone or more hydrophobic membranes situated after the cooling system, orsituated between the reaction chamber and the cooling system, or both,to remove a portion of water from the gas flow comprising the oxygen;and an electronic control unit that regulates a flow rate of oxygen fromthe device; wherein the device generates a constant flow of oxygen up toat least about 8 L/min, at a temperature of less than about 40° C. formore than about 30 minutes.
 2. The device of claim 1, wherein the deviceadditionally comprises a catalytic filter situated in fluidcommunication between the outlet of the reaction chamber and the inletof the cooling system, wherein the catalytic filter comprises a catalystfor the decomposition of hydrogen peroxide to oxygen and water.
 3. Thedevice of claim 1, wherein the cooling system additionally comprises aheat sink.
 4. The device of claim 3, wherein the cooling systemcomprises one or more fans.
 5. The device of claim 1, wherein thecondenser is configured for the draining of liquid water throughout thelength of the condenser.
 6. The device of claim 5, wherein the liquidwater is drained from the condenser immediately and continuously.
 7. Thedevice of claim 1, wherein the cooling system additionally comprises areceptacle for collecting the condensed water.
 8. The device of claim 1,wherein the feed flow regulator comprises a pump.
 9. The device of claim8, wherein the pump is selected from the group consisting of adisplacement pump, a peristaltic pump, a syringe pump, a piston pump, aplunger pump, a screw pump and a reciprocating pump.
 10. The device ofclaim 1, wherein the catalyst is selected from a metal, a metalloid, analloy of a metal, an alloy of a metalloid, a metal oxide, and a compoundof a metalloid, or mixtures thereof.
 11. The device of claim 10, whereinthe catalyst comprises manganese dioxide.
 12. The device of claim 1,wherein the aqueous hydrogen peroxide solution is at least about 15%hydrogen peroxide.
 13. The device of claim 12, wherein the aqueoushydrogen peroxide solution is between about 30% to about 70% hydrogenperoxide.
 14. The device of claim 1, wherein each of the one or morehydrophobic membranes comprises a material selected from acrylicco-polymers, polytetrafluoroethylene (PTFE), andpolyvinylidenedifluoride (PVDF).
 15. The device of claim 1, wherein theflow of oxygen from the device is directly proportional to a rate ofintroduction of the aqueous hydrogen peroxide solution into the reactionchamber during device operation.
 16. The device of claim 1, wherein theoxygen flow exiting the device comprises less than about 1 ppm ofhydrogen peroxide.
 17. The device of claim 16, wherein the oxygen flowexiting the device comprises less than about 0.5 ppm of hydrogenperoxide.
 18. The device of claim 1, wherein the oxygen that exits thedevice is not more than about 10° C. above the ambient temperature.